Beam-pointing verification using x-ray pinhole cameras on the 60-beam OMEGA laser

On the OMEGA laser system, the beam-pointing accuracy is verified by irradiating a 4 mm diameter Au-coated spherical target with ∼23 kJ of laser energy. Up to ten x-ray pinhole cameras record the x-ray emission from all 60-beam spots. A new set of algorithms has been developed to improve the accurac...

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Bibliographic Details
Published in:Review of scientific instruments 2022-10, Vol.93 (10), p.103524-103524
Main Authors: Stoeckl, C., Cao, D., Ceurvorst, L., Kalb, A., Kwiatkowski, J., Shvydky, A., Theobald, W.
Format: Article
Language:English
Subjects:
Algorithms
Back propagation
Emission
Fast Fourier transformations
Gold coatings
Illumination
Luminance distribution
Pinhole cameras
Pixels
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Summary:On the OMEGA laser system, the beam-pointing accuracy is verified by irradiating a 4 mm diameter Au-coated spherical target with ∼23 kJ of laser energy. Up to ten x-ray pinhole cameras record the x-ray emission from all 60-beam spots. A new set of algorithms has been developed to improve the accuracy of the pointing evaluation. An updated edge-finding procedure allows one to infer the center of the sphere with subpixel accuracy. A new approach was introduced to back-propagate the pixel locations on the 2D image to the 3D surface of the sphere. A fast Fourier transform-based de-noising method significantly improves the signal-to-noise of the data. Based on the beam-pointing analysis, hard-sphere calculations of the laser-drive illumination uniformity on the target surface and the decomposition of the illumination distribution into lower order modes (1–10) are evaluated.
ISSN:0034-6748
1089-7623
DOI:10.1063/5.0098941